The present invention relates to a compound and method for preserving and healing dental pulp.
The dental pulp is a delicate connective tissue abundantly interspersed with tiny blood vessels, unmyelinated nerves, lymphatics and embryonic connective tissue cells. In this respect the pulp is similar in its make-up to other connective tissues throughout the body in that it reacts to bacterial infection or to other stimuli with an inflammatory response. The pulp, however, has some unique anatomic features that alter the nature and course of this response. Specifically, the calcified walls of dentin act as a firm enclosure for the pulpal connective tissues which limits the amount of usual tissue swelling that occurs in the hyperemic and edematous phases of inflammation. The blood vessels that supply the pulp enter the tooth through tiny apical openings, and once the tooth root has calcified, it is impossible for a collateral blood supply to develop through the hardened dentin and penetrate this inflammed tissue. In other connective tissues throughout the body, a collateral circulation would readily develop in the presence of inflammation. The inaccessibility of pulp connective tissue to external treatment has generally precluded its continued survival even after a mild injury, and hence many pulps have been sacrificed for lack of a truly effective treatment.
Most pulpitis results from the progressive spread of dental caries in which bacterial infection of the pulp occurs. Pulpitis may also arise as a result of chemical irritation of the pulp, as is seen in exposed pulps to which some medicament is applied. This may also occur with intact pulps beneath deep cavities into which irritating filling material has been inserted. In such cases, these substances penetrate and traverse the dentinal tubules into the pulp. Pulpitis itself is caused by a variety of circumstances, each producing a deleterious effect on the dental pulp. It occurs frequently in a tooth with a large carious lesion or where the restoration is defective, and there has been recurrent caries.
Pain is elicited in the early stages of pulpitis, even when the inflammatory reaction involves only a part of the pulp. Cold sensitivity is usually most notable, and pain may persist even after the thermal stimuli has been eliminated. Sensitivity to both cold and heat is common in the presence of any type of pulpitis, and as more of the pulp becomes involved, the pain increases in intensity. THe pain may be continuous and may even increase in severity due to changes in body position, such as bending over or lying down. When pulp tested, the tooth will exhibit extreme sensitivity when compared to the adjacent healthy teeth. This condition usually continues on to necrosis of the pulp and abscess formation with sensitivity ultimately being lost when pulp tested.
Severe pain is more likely to be present when the opening to the pulp is small. Pulpal pressure increases because the inflammatory exudate has no way to escape, and there is a rapid spread of inflammation throughout the pulp with resultant pain and necrosis. Until the necrosis extends beyond the pulp tissue within the root, the tooth is not particularly sensitive to percusion. When the opening to the pulp is large, the opportunity for a build-up of pressure is less. In such a case, the inflammatory process does not tend to spread as rapidly throughout the pulp and the pain experienced is of a dull, throbbing nature.
Prior to the present invention, there has not been a predictably successful treatment for pulpitis. In fact, the consensus has always been that once pulpitis occurs, the damage is irreparable, leading to abscess formation. If these teeth are to be retained, the pulps usually require extirpation, through cleansing, and sealing of the pulp chambers and root canals with a suitable material. Many medicaments have been tried to preserve the diseased pulpal tissues. Medicated cements, calcium hydroxide, zinc oxide and eugenol, steroids, antibiotics, etc. have been tried for this purpose but the success rate for these medications has been poor for the short term, and even less encouraging for the long term.
In accordance with the present invention, it has now been found that by adding a few drops of potassium nitrate to a zinc oxide-eugenol paste or other suitable vehicles, a commpound results which when used for the capping of dental pulp prevents most pulp degeneration and abscess formation from occurring. The instant applicant has heretofore recognized the amazing effectiveness of potassium nitrate in connection with the treatment of other dental problems and reference is made to applicant's U.S. Pat. No. 3,863,006 dated Jan. 28, 1975, entitled "Method for Desensitizing Teeth" and U.S. Pat. No. 4,191,750 dated Mar. 4, 1980, entitled "Method for Treating Canker Sores". However, prior to the instant invention, it was not known that the use of potassium nitrate as one of the essential ingredients in a compound used for the capping of dental pulp would prevent most pulpal degeneration and abscess formation from occurring. In the Gorgas-Dental Medicine publication cited in the aforesaid Pat. No. 4,191,750, it is suggested (on page 262) that nitrate of potassium has been recommended for use in the incipient stages of alveolar abscess, being introduced into the pulp canal and secured by a temporary filling in the crown cavity of the tooth. However, the gist of the present invention is to cap the dental pulp with the potassium nitrate containing compound prior to any abscess formation, since once an abscess has started to form, the compound and treatment of the present invention is of little effect.